Subtle to no attentional differences have been broadly observed when using gaze and arrows as orienting cues. However, recent studies have found opposite effects when they are used as targets in spatial interference tasks, with arrows eliciting faster responses when their position is congruent with the indicated direction and gaze producing faster responses in incongruent conditions. In two preregistered experiments aimed at exploring the mechanisms supporting these findings, we examined whether the congruency sequence effects (CSE) elicited by gaze and arrows generalized from one stimulus to another, using an intrablock design where the type of stimuli was manipulated on a trial-by-trial basis. Typical CSE were observed for arrows, with a decrease of congruency effects after incongruent trials, and reversed CSE for gaze, with an increased inversion of congruency effects after incongruent trials. Both patterns occurred independently of the preceding type of target, showing that congruency effects can decrease after positive outcomes (e.g., arrow trials following an incongruent gaze trial), and generalized across different nonsocial and social stimuli as shown in a third experiment. These results are consistent with the coexistence of a shared spatial interference component between gaze and arrow trials, potentially responsible for the CSE obtained in switching target trials, and an additional social dimension, exclusively engaged in gaze trials.

Vigilance—maintaining a prolonged state of preparation to detect and respond to specific yet unpredictable environmental changes—usually decreases across prolonged tasks, causing potentially severe real-life consequences, which could be mitigated through transcranial direct current stimulation (tDCS). The present study aimed at replicating previous mitigatory effects observed with anodal high-definition tDCS (HD-tDCS) over the right posterior parietal cortex (rPPC) while extending the analyses on electrophysiological measures associated with vigilance. In sum, 60 participants completed the ANTI-Vea task while receiving anodal (1.5 mA, n = 30) or sham (0 mA, n = 30) HD-tDCS over the rPPC for ~ 28 min. EEG recordings were completed before and after stimulation. Anodal HD-tDCS specifically mitigated executive vigilance (EV) and reduced the alpha power increment across time-on-task while increasing the gamma power increment. To further account for the observed behavioral and physiological outcomes, a new index of Alphaparietal/Gammafrontal is proposed. Interestingly, the increment of this Alphaparietal/Gammafrontal Index with time-on-task is associated with a steeper EV decrement in the sham group, which was mitigated by anodal HD-tDCS. We highlight the relevance of replicating mitigatory effects of tDCS and the need to integrate conventional and novel physiological measures to account for how anodal HD-tDCS can be used to modulate cognitive performance.

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